Manfred & Andrew,

I am happy with the patch.This seems to have fixed slab fragmentation
problem with scsi_debug tests.

But I still have issue with my scsi-debug tests. I don't think they
are related to this patch. When I do,

	while :
	do
		simulate 1000 scsi-debug disks
		freeup 1000 scsi-debug disks
	done

I see size-64 "inuse" objects increasing. Eventually, it fills
up entire low-mem. I guess while freeing up scsi-debug disks,
is not cleaning up all the allocations :(

But one question I have is - Is it possible to hold size-64 slab,
because it has a management allocation (slabp - 40 byte allocations)
from alloc_slabmgmt() ?  I remember seeing this earlier. Is it worth
moving all managment allocations to its own slab ? should I try it ?

Thanks,
Badari

On Sat, 2004-10-09 at 13:37, Manfred Spraul wrote:

Hi Andrew,

attached is a patch that fixes the fragmentation that Badri noticed with 
kmem_cache_alloc_node. Could you add it to the mm tree? The patch is 
against 2.6.9-rc3-mm3.

Description:
kmem_cache_alloc_node tries to allocate memory from a given node. The 
current implementation contains two bugs:
- the node aware code was used even for !CONFIG_NUMA systems. Fix: 
inline function that redefines kmem_cache_alloc_node as kmem_cache_alloc 
for !CONFIG_NUMA.
- the code always allocated a new slab for each new allocation. This 
caused severe fragmentation. Fix: walk the slabp lists and search for a 
matching page instead of allocating a new page.
- the patch also adds a new statistics field for node-local allocs. They 
should be rare - the codepath is quite slow, especially compared to the 
normal kmem_cache_alloc.

Badri: Could you test it?
Andrew, could you add the patch to the next -mm kernel? I'm running it 
right now, no obvious problems.

Signed-Off-By: Manfred Spraul <redacted>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"aart@kvack.org"> aart@kvack.org </a>